1. Technical Field
The present invention relates to a display panel in which a remaining portion of a slant mark for testing accuracy of a position at which an individual substrate is segmented from a large sized substrate is formed and to a manufacturing method thereof. In particular, the invention relates to a display panel in which a remaining portion of a slant mark formed by a plurality of scale lines arranged in parallel to each other in a stepwise manner at a position apart from a corner of an individual substrate is formed, and to a manufacturing method thereof.
2. Related Art
A flat panel such as a liquid crystal display panel, an organic electro luminescence display panel, or the like has characteristics that it is lightweight, thin, and it is operated with low power consumption, and the flat panel is used in many electronic apparatuses. When the flat panel is manufactured, a method is generally employed in which a large sized panel formed by a glass substrate is segmented into individual panels having a predetermined size. As is disclosed in JP-A-2001-166121 and JP-A-2007-304501, the segment method is performed by positioning the large sized panel based on alignment marks formed therein, and by segmenting the large sized panel by a cutter (or laser). The alignment mark is provided at each corner of the individual substrate, and has a gap width (tolerance) for showing allowance of deviation of the cutter. The cutter is passed through within the gap of the alignment mark and the large sized panel is segmented. Herewith, the individual panel is manufactured. Then, after segmented into the individual panel, testing of whether the individual panel is cut within the tolerance or not can be performed by examining the segmented state of the alignment mark remained in the individual panel.
Recently, in order to improve shape accuracy of the display panel, not only a size tolerance of the display panel, but also a slant tolerance (for example, ±0.1 degrees) of a segment line (hereinafter, line after cut is referred to as segment line, and target line before cut is referred to as virtual cutting line) is added in the display panel. The conventional alignment mark is provided for the purpose of positioning of a cutter when segmented, so that only a gap having a predetermined width showing an acceptable range of the segment positional deviation is formed in the alignment mark. In addition, after segmented, the alignment mark is also segmented. Consequently, in the conventional alignment mark, it has been difficult to measure a cut size with high accuracy, and in particular, it has been impossible to directly examine the slant of the segment line. Further, since the conventional alignment mark is formed at a corner of the individual display panel, there is a case that the alignment mark is cracked, and testing of whether the individual panel is cut within a tolerance or not can not be performed.